珠江口盆地东部海域天然气水合物钻探结果及其成藏要素研究

Natural gas hydrate accumulation elements and drilling results analysis in the eastern part of the Pearl River Mouth Basin

天然气水合物被普遍认为将是21世纪最具潜力的接替煤炭、石油和天然气的新型洁净能源之一,同时也是目前尚未开发的储量巨大的一种新能源。广州海洋地质调查局从1999年起,在南海北部陆坡进行了多年的地球物理、地球化学以及地质综合调查,获取了大量与天然气水合物赋存有关的各种地质信息,并分别于2007年在神狐海域和2013年在珠江口盆地东部海域实施钻探,均成功获取了天然气水合物样品,特别是2013年度在珠江口盆地东部海域的钻探航次中,获取了高纯度、多种产状类型的天然气水合物实物样品。以上调查及钻探成果,证实了我国南海存在巨大的天然气水合物(简称水合物)资源前景。本文简要介绍了我国珠江口盆地东部海域2013年的主要钻探结果。本研究在钻前,将2013年钻区的水合物成藏条件与对世界上多个天然气水合物钻探区进行综合对比分析。结果表明,气源条件、稳定条件、气体运移条件和储集条件是该钻区水合物成藏的最重要控制因素(成藏要素)。经过分析该区这些要素的特征,预测本区应发育渗漏型水合物。2013年钻探结果揭示该区同时存在分散型和渗漏型水合物,说明控制该区水合物形成和分布的因素更为复杂。

Natural gas hydrate is generally considered to be one of the most promising new type of clean energies to replace coal,oil and natural gas,and it has enormous reserves but still untapped.Guangzhou Marine Geological Survey carried out geophysical,geochemical and comprehensive geological investigation in the northern slope of the South China Sea from the year of 1999,obtained a lot of geological information about gas hydrate occurrence,and implemented drilling in year 2007 in the Shenhu area and in year 2013 in the eastern part of the Pearl River Mouth Basin;both of them acquired gas hydrate samples successfully,especially the voyage of drilling in year 2013 in the eastern part of the Pearl River Mouth Basin had gotten high purity,new type of gas hydrate samples.The result of above investigation and drilling confirmed the existence of a huge resource prospects of gas hydrate in South China Sea.This paper gives a brief introduction of the main results of the drilling in year 2013 in the eastern part of the Pearl River Mouth Basin.This study makes contrastive analysis between several hydrate drilling areas worldwide and the accumulation condition in the eastern part of the Pearl River Mouth Basin before the drilling.The result indicated that gas source,stable environment,gas migration and reservoir conditions are essential factors of gas hydrate accumulation.According to the analysis of the characteristics of these factors,we forecasted the formation of seeped hydrate in this area.The drilling in year 2013 revealed the coexistence of the disseminated hydrate and seeped hydrate in this area and illustrated that the controlling factors of the formation and distribution of gas hydrate in this area were more complex.